<!--
@SCRIPT:
  header.accessibilityAttributeNames.has(AXDOMIdentifier)
  header.accessibilityAttributeValue(AXDOMIdentifier)
  header.AXChildren[0].accessibilityAttributeNames.has(AXDOMIdentifier)
  header.AXChildren[0].accessibilityAttributeValue(AXDOMIdentifier)
-->
<!DOCTYPE html>
<header id="header"><button>button</button></header>
